/**
 * Software License, Version 1.0
 * 
 * Copyright 2003 The Trustees of Indiana University.  All rights reserved.
 * 
 *
 *Redistribution and use in source and binary forms, with or without 
 *modification, are permitted provided that the following conditions are met:
 *
 *1) All redistributions of source code must retain the above copyright notice,
 * the list of authors in the original source code, this list of conditions and
 * the disclaimer listed in this license;
 *2) All redistributions in binary form must reproduce the above copyright 
 * notice, this list of conditions and the disclaimer listed in this license in
 * the documentation and/or other materials provided with the distribution;
 *3) Any documentation included with all redistributions must include the 
 * following acknowledgement:
 *
 *"This product includes software developed by the Community Grids Lab. For 
 * further information contact the Community Grids Lab at 
 * http://communitygrids.iu.edu/."
 *
 * Alternatively, this acknowledgement may appear in the software itself, and 
 * wherever such third-party acknowledgments normally appear.
 * 
 *4) The name Indiana University or Community Grids Lab or NaradaBrokering, 
 * shall not be used to endorse or promote products derived from this software 
 * without prior written permission from Indiana University.  For written 
 * permission, please contact the Advanced Research and Technology Institute 
 * ("ARTI") at 351 West 10th Street, Indianapolis, Indiana 46202.
 *5) Products derived from this software may not be called NaradaBrokering, 
 * nor may Indiana University or Community Grids Lab or NaradaBrokering appear
 * in their name, without prior written permission of ARTI.
 * 
 *
 * Indiana University provides no reassurances that the source code provided 
 * does not infringe the patent or any other intellectual property rights of 
 * any other entity.  Indiana University disclaims any liability to any 
 * recipient for claims brought by any other entity based on infringement of 
 * intellectual property rights or otherwise.  
 *
 *LICENSEE UNDERSTANDS THAT SOFTWARE IS PROVIDED "AS IS" FOR WHICH NO 
 *WARRANTIES AS TO CAPABILITIES OR ACCURACY ARE MADE. INDIANA UNIVERSITY GIVES
 *NO WARRANTIES AND MAKES NO REPRESENTATION THAT SOFTWARE IS FREE OF 
 *INFRINGEMENT OF THIRD PARTY PATENT, COPYRIGHT, OR OTHER PROPRIETARY RIGHTS. 
 *INDIANA UNIVERSITY MAKES NO WARRANTIES THAT SOFTWARE IS FREE FROM "BUGS", 
 *"VIRUSES", "TROJAN HORSES", "TRAP DOORS", "WORMS", OR OTHER HARMFUL CODE.  
 *LICENSEE ASSUMES THE ENTIRE RISK AS TO THE PERFORMANCE OF SOFTWARE AND/OR 
 *ASSOCIATED MATERIALS, AND TO THE PERFORMANCE AND VALIDITY OF INFORMATION 
 *GENERATED USING SOFTWARE.
 */
package cgl.narada.wsinfra.wse.matching;

import java.util.Enumeration;
import java.util.Hashtable;

import cgl.narada.wsinfra.exception.DeploymentException;
/**
    This is a class which allows users to register their custom engines at
    run-time. For e.g. there could implementations of this for XPath, XQuery,
    String Topics and Regular Expressions. Other custom capabilities can be
    added by the developers and registered at run-time.

    @author Shrideep Pallickara
    $Date: 2005/07/29 22:41:30 $
    $Revision: 1.3 $
*/


public class MatchingCapabilityFactory {

  private static final MatchingCapabilityFactory instance =
  new MatchingCapabilityFactory();
  private Hashtable capabilities;

  private String moduleName = "MatchingCapabilityFactory: ";

  private MatchingCapabilityFactory() {
    capabilities = new Hashtable();
  }


  public static MatchingCapabilityFactory getInstance() {
    return instance;
  }

  /** Gets the list of dialects registered with this Factory */
  public Enumeration getSupportedDialects() {
    return capabilities.keys();
  }


  /** Check to see if capabilities related to a specific dialect has been
      registered */
  public boolean isSupportedDialect(String dialect) {
    if (dialect == null) {
      return false;
    }

    if (capabilities.containsKey(dialect) ) {
      return true;
    }

    return false;
  }


  /** Retrieves the matching capability corresponding to a specific dialect.
      If a capability has not been previously registered, a NULL will be
      returned. */
  public MatchingCapability getCapability(String dialect) {
    if (dialect == null) {
      return null;
    }

    Object capability = capabilities.get(dialect);

    if (capability != null) {
      return (MatchingCapability) capability;
    }

    return null;
  }


  /** Register a specific capability. */
  public void registerMatchingCapability(MatchingCapability matchingCapability)
    throws DeploymentException {
    if (matchingCapability == null) {
      throw new DeploymentException(moduleName +
				    "Trying to register a NULL capability!");
    }

    String dialect = matchingCapability.getDialect();

    if (dialect == null) {
      throw new DeploymentException(moduleName +
				    "Capability has a NULL dialect!");
    }

    if (isSupportedDialect(dialect) ) {
      throw
	new DeploymentException(moduleName +
				"Matching capability previously registered!");
    }

    capabilities.put(dialect, matchingCapability);


  }


}
